1. Field of the Invention
The present invention relates generally to a position sensor and more specifically to a position sensor which is suited for use in rugged environments such as a automotive vehicle suspension which is adapted to permit the clearance between the bottom of the vehicle and the road surface to be adjusted.
2. Description of the Prior art
In automotive vehicle suspensions which are adapted to permit the clearance between the vehicle and the road surface to be selectively adapted it has been proposed to equip members of the suspension such as shock absorbers with sensing arrangements which sense the degree to which the absorbers are exended. One example of such an arrangement is disclosed in Japanese Utility Model First Provisional Publication No. 57-88609. In this arrangement the absorber is constructed in a manner to include a non-magnetic non-conductive tubular sleeve member 1 in which a coil 2 is buried. The variation in the inductance developed by this coil 2 is used as a indication of the degree to which the shock absorber is extended.
However, in the event that the shock absorber is equipped with or disposed in the near vicinity of an electromagnetic valve or the like for the purposes of controlling the height of the vehicle, the noise generated by the operation of the valve is picked up by the inductance coil and interferes with the operation of the sensor. Further, the production of the outer sleeve member is relatively expensive.